In conventional windscreen wipers, between the main wiper arm and the lever driving the wiper arm, there exists a drive shaft which oscillates so as to transfer the motion of the lever to the wiper arm. Generally, this drive shaft is surrounded by a housing supporting it in the surrounding vehicle panel. In fact, this housing is part of a pivot assembly comprising a plurality of parts required to support, seal and allow rotation of the drive shaft. Where the drive shaft is operably connected to the driving lever inside the vehicle, at a first end, a bearing is provided. Additionally, a bearing is provided where the wiper arm is operably connected to the drive shaft outside the vehicle at a second end of the assembly. The assembly at this second end of the drive shaft also includes a sealing `O` ring, a thrust bearing washer and a circlip. In order to take up the length tolerances and to bias the pivot assembly towards the `O` ring seal to prevent water ingress, at the first lever end of the shaft there is also provided a wave washer. In totality, 7 parts make up a conventional pivot assembly for drive shafts of this type.
A typical arrangement of this type is illustrated in FIGS. 3 and 4, wherein the drive shaft 10 is supported in a housing 24 in the surrounding vehicle panel and connects the upper end of shaft on the outside of the vehicle to the wiper arm 11 and the lower end of the shaft on the inside of the vehicle to a lever 12 providing oscillating movement to the drive shaft. At this lower end of the shaft a bearing 19 is provided. Another bearing 18 is also provided at the upper end of the shaft on the outside of the vehicle. At this upper end of the drive shaft a sealing `O` ring (not shown) is also provided as well as a thrust bearing washer 16 and a circlip 15. Typically, the neck portion 17 of housing 24 protrudes through a hole in the vehicle cowl. To take up the length tolerances at the lower end of the shaft, inside the vehicle, a wave washer 20 is provided.
The manufacture of assemblies of the type described is complicated due to the large number of parts required and is therefore difficult to automate. A further disadvantage is that these assemblies, due to their intricacy, are also expensive to produce.